NASA Facts National Aeronautics and Space Administration

Total Page:16

File Type:pdf, Size:1020Kb

NASA Facts National Aeronautics and Space Administration NASA Facts National Aeronautics and Space Administration Dryden Flight Research Center P.O. Box 273 Edwards, California 93523 Voice 661-276-3449 FAX 661-276-3566 [email protected] FS-1994-11-035 DFRC D-558-II D-558-II Skyrocket being launched from a P2B. The Douglas D-558-II "Skyrockets" were among the early transonic research airplanes like the X-1, X-4, X-5, and X-92A. Three of the single-seat, swept-wing aircraft flew from 1948 to 1956 in a joint program involving the National Advisory Committee for Aeronautics (NACA), with its flight research done at the NACA's Muroc Flight Test Unit in Calif., redesignated in 1949 the High-Speed Flight Research Station (HSFRS); the Navy- Marine Corps; and the Douglas Aircraft Co. The HSFRS is now known as the NASA Dryden Flight Research Center. The Skyrocket made aviation history when it became the first airplane to fly twice the speed of sound. The II in the aircraft's designation referred to the fact that the Skyrocket was the phase-two version of what had originally been conceived as a three-phase program, with the phase-one aircraft having straight wings. The third 1 phase, which never came to fruition, would have powered aircraft and funded the X-1, while the NACA involved constructing a mock-up of a combat-type and Navy preferred a more conservative design and aircraft embodying the results from the testing of the pursued the D-558, with the NACA also supporting phase one and two aircraft. the X-1 research. Douglas pilot John F. Martin made the first flight at The Navy contracted with Douglas to design the Muroc Army Airfield (later renamed Edwards Air airplane, and in the course of the design process, the Force Base) in Calif. on February 4, 1948. The goals D-558 came to be divided into two separate phases, of the program were to investigate the characteristics with phase one being a straight-wing turbojet aircraft of swept-wing aircraft at transonic and supersonic and phase two consisting of a swept-wing design with speeds with particular attention to pitch-up turbojet and rocket propulsion. At the NACA's sug- (uncommanded rotation of the nose of the airplane gestion, based on the research of Robert Jones at upwards)--a problem prevalent in high-speed service Langley and captured German documents, Douglas aircraft of that era, particularly at low speeds during and the Navy had agreed to the swept-wing design, take-off and landing and in tight turns. and to provide sufficient power to propel the swept- wing airplane past Mach 1, they also agreed to add The three aircraft gathered a great deal of data about rocket propulsion. pitch-up and the coupling of lateral (yaw) and longitu- dinal (pitch) motions; wing and tail loads, lift, drag, Then, to fit both a turbojet and rocket engine in the and buffeting characteristics of swept-wing aircraft at phase two aircraft required a new fuselage. Like the transonic and supersonic speeds; and the effects of the D-558-I, the Skyrocket featured a horizontal stabilizer rocket exhaust plume on lateral dynamic stability high on the vertical tail to avoid the wake from the throughout the speed range. (Plume effects were a wing. As with the X-1 and the D-558-1, the Skyrocket new experience for aircraft.) The number three air- also featured, at NACA suggestion, a horizontal craft also gathered information about the effects of stabilizer that was thinner than the wing and movable external stores (bomb shapes, drop tanks) upon the in flight so as to avoid simultaneous shock wave aircraft's behavior in the transonic region (roughly 0.7 effects for the wing and horizontal tail and to provide to 1.3 times the speed of sound). pitch (nose up or down) control when shock waves made the elevators ineffective. While Douglas was In correlation with data from other early transonic constructing the D-558-IIs, the NACA continued to research aircraft such as the XF-92A, this information furnish the contractor data it needed on aircraft perfor- contributed to solutions to the pitch-up problem in mance based on tests in Langley wind tunnels and swept-wing aircraft. with rocket-propelled models from the Wallops Island Pilotless Aircraft Research Station. Design Program History The need for transonic research airplanes grew out of two conditions that existed in the early 1940s. One The three airplanes flew a total of 313 times--123 by was the absence of accurate wind tunnel data for the the number one aircraft (Bureau No. 37973--NACA speed range from roughly Mach 0.8 to 1.2. The other was the fact that fighter aircraft like the P-38 "Light- ning" were approaching these speeds in dives and breaking apart from the effects of compressibility-- increased density and disturbed airflow as the speed approached that of sound, creating shock waves. People in the aeronautics community--especially the NACA, the Army Air Forces (AAF), and the Navy-- agreed on the need for a research airplane with enough structural strength to withstand compressibility effects in the transonic region. The AAF preferred a rocket- D-558-II Skyrocket on the Lakebed at Edwards AFB. 2 143), 103 by the second Skyrocket (Bureau No. The NACA engineers studied the behavior of the 37974--NACA 144), and 87 by airplane number three aircraft before beginning their own flight research in (Bureau No. 37975--NACA 145). Skyrocket 143 flew the airplane in September 1951. Over the next couple all but one of its missions as part of the Douglas of years, NACA pilot A. Scott Crossfield flew the contractor program to test the airplane's performance. airplane 20 times to gather data on longitudinal and lateral stability and control, wing and tail loads, and NACA aircraft 143 was initially powered by a lift, drag, and buffeting characteristics at speeds up to Westinghouse J-34-40 turbojet engine configured only Mach 1.878. for ground take-offs, but in 1954-55 the contractor modified it to an all-rocket air-launch capability At that point, Marine Lt. Col. Marion Carl flew the featuring an LR8-RM-6, 4-chamber Reaction Motors airplane to a new (unofficial) altitude record of 83,235 engine rated at 6,000 pounds of thrust at sea level (the feet on August 21, 1953, and to a maximum speed of Navy designation for the Air Force's LR-11 used in Mach 1.728. the X-1). In this configuration, NACA research pilot John McKay flew the airplane only once for familiar- Following Carl's completion of these flights for the ization on September 17, 1956. The 123 flights of Navy, NACA technicians at the High-Speed Flight NACA 143 served to validate wind-tunnel predictions Research Station (HSFRS) near Mojave, Calif., outfit- of the airplane's performance, except for the fact that ted the LR-8 engine's cylinders with nozzle extensions the airplane experienced less drag above Mach 0.85 to prevent the exhaust gas from affecting the rudders than the wind tunnels had indicated. at supersonic speeds. This addition also increased the engine's thrust by 6.5 percent at Mach 1.7 and 70,000 NACA 144 also began its flight program with a feet. turbojet powerplant. NACA pilots Robert A. Champine and John H. Griffith flew 21 times in this Even before Marion Carl had flown the Skyrocket, configuration to test airspeed calibrations and to HSFRS Chief Walter C. Williams had petitioned research longitudinal and lateral stability and control. In the process, during August of 1949 they encoun- tered pitch-up problems, which NACA engineers recognized as serious because they could produce a limiting and dangerous restriction on flight perfor- mance. Hence, they determined to make a complete investigation of the problem. In 1950, Douglas replaced the turbojet with an LR-8 rocket engine, and its pilot, William B. Bridgeman, flew the aircraft seven times up to a speed of Mach 1.88 (1.88 times the speed of sound) and an altitude of Graphic showing the D-558-II Wing Configurations. 79,494 feet (the latter an unofficial world's altitude record at the time, achieved on August 15, 1951). In the rocket configuration, a Navy P2B (Navy version of NACA headquarters unsuccessfully to fly the aircraft the B-29) launched the airplane at approximately to Mach 2 to garner the research data at that speed. 30,000 feet after taking off from the ground with the Finally, after Crossfield had secured the agreement of Skyrocket attached beneath its bomb bay. During the Navy's Bureau of Aeronautics, NACA director Bridgeman's supersonic flights, he encountered a Hugh L. Dryden relaxed the organization's usual violent rolling motion known as lateral instability that practice of leaving record setting to others and con- was less pronounced on the Mach 1.88 flight on sented to attempting a flight to Mach 2. August 7, 1951, than on a Mach 1.85 flight in June when he pushed over to a low angle of attack (angle of In addition to adding the nozzle extensions, the NACA the fuselage or wing to the prevailing wind direction). flight team at the HSFRS chilled the fuel (alcohol) so 3 more could be poured into the tank and waxed the wind-tunnel test results with actual flight values, fuselage to reduce drag. With these preparations and enhancing the abilities of designers to produce more employing a flight plan devised by project engineer capable aircraft for the armed services, especially Herman O.
Recommended publications
  • Concorde Is a Museum Piece, but the Allure of Speed Could Spell Success
    CIVIL SUPERSONIC Concorde is a museum piece, but the allure Aerion continues to be the most enduring player, of speed could spell success for one or more and the company’s AS2 design now has three of these projects. engines (originally two), the involvement of Air- bus and an agreement (loose and non-exclusive, by Nigel Moll but signed) with GE Aviation to explore the supply Fourteen years have passed since British Airways of those engines. Spike Aerospace expects to fly a and Air France retired their 13 Concordes, and for subsonic scale model of the design for the S-512 the first time in the history of human flight, air trav- Mach 1.5 business jet this summer, to explore low- elers have had to settle for flying more slowly than speed handling, followed by a manned two-thirds- they used to. But now, more so than at any time scale supersonic demonstrator “one-and-a-half to since Concorde’s thunderous Olympus afterburn- two years from now.” Boom Technology is working ing turbojets fell silent, there are multiple indi- on a 55-seat Mach 2.2 airliner that it plans also to cations of a supersonic revival, and the activity offer as a private SSBJ. NASA and Lockheed Martin appears to be more advanced in the field of busi- are encouraged by their research into reducing the ness jets than in the airliner sector. severity of sonic booms on the surface of the planet. www.ainonline.com © 2017 AIN Publications. All Rights Reserved. For Reprints go to Shaping the boom create what is called an N-wave sonic boom: if The sonic boom produced by a supersonic air- you plot the pressure distribution that you mea- craft has long shaped regulations that prohibit sure on the ground, it looks like the letter N.
    [Show full text]
  • 2. Afterburners
    2. AFTERBURNERS 2.1 Introduction The simple gas turbine cycle can be designed to have good performance characteristics at a particular operating or design point. However, a particu­ lar engine does not have the capability of producing a good performance for large ranges of thrust, an inflexibility that can lead to problems when the flight program for a particular vehicle is considered. For example, many airplanes require a larger thrust during takeoff and acceleration than they do at a cruise condition. Thus, if the engine is sized for takeoff and has its design point at this condition, the engine will be too large at cruise. The vehicle performance will be penalized at cruise for the poor off-design point operation of the engine components and for the larger weight of the engine. Similar problems arise when supersonic cruise vehicles are considered. The afterburning gas turbine cycle was an early attempt to avoid some of these problems. Afterburners or augmentation devices were first added to aircraft gas turbine engines to increase their thrust during takeoff or brief periods of acceleration and supersonic flight. The devices make use of the fact that, in a gas turbine engine, the maximum gas temperature at the turbine inlet is limited by structural considerations to values less than half the adiabatic flame temperature at the stoichiometric fuel-air ratio. As a result, the gas leaving the turbine contains most of its original concentration of oxygen. This oxygen can be burned with additional fuel in a secondary combustion chamber located downstream of the turbine where temperature constraints are relaxed.
    [Show full text]
  • For the Full Potential Equation of Transonic Flow*
    MATHEMATICS OF COMPUTATION VOLUME 44, NUMBER 169 JANUARY 1985, PAGES 1-29 Entropy Condition Satisfying Approximations for the Full Potential Equation of Transonic Flow* By Stanley Osher, Mohamed Hafez and Woodrow Whitlow, Jr. Abstract. We shall present a new class of conservative difference approximations for the steady full potential equation. They are, in general, easier to program than the usual density biasing algorithms, and in fact, differ only slightly from them. We prove rigorously that these new schemes satisfy a new discrete "entropy inequality", which rules out expansion shocks, and that they have sharp, steady, discrete shocks. A key tool in our analysis is the construction of an "entropy inequality" for the full potential equation itself. We conclude by presenting results of some numerical experiments using our new schemes. I. Introduction. The full potential equation is a common model for describing supersonic and subsonic flow close to the speed of sound. The flow is assumed to be that of a perfect gas, and the assumptions of irrotationality and constant entropy are made. The resulting equation is a single nonlinear partial differential equation of second order, which changes type from hyperbolic to elliptic, as the flow goes from supersonic to subsonic. Flows with a supersonic component generally have solutions with shocks, so the conservation form of the equation is important. This formulation, (FP), is one of three conservative formulations used for inviscid transonic flows. The other two are transonic small-disturbance equation, (TSD), and Euler equation, (EU), which is the exact inviscid formulation. The FP formulation is the most efficient of the three in terms of accuracy-to-cost ratio for a wide range of inviscid transonic flow applications for real geometries.
    [Show full text]
  • Mathematical Problems in Transonic Flow
    Canad. Math. Bull. Vol. 29 (2), 1986 MATHEMATICAL PROBLEMS IN TRANSONIC FLOW BY CATHLEEN SYNGE MORAWETZ ABSTRACT. We present an outline of the problem of irrotational com­ pressible flow past an airfoil at speeds that lie somewhere between those of the supersonic flight of the Concorde and the subsonic flight of commercial airlines. The problem is simplified and the important role of modifying the equations with physics terms is examined. The subject of my talk is transonic flow. But before I can talk about transonics I must talk about flight in general. There are two ways of staying off the ground -— by rocket propulsion (the Buck Rogers mode) or by using the forces that permit gliding or for that matter sailing. Every form of man's flight is some compromise between these two extremes. The one that most mathematicians begin their learning on is incompressible, steady (no time dependence), irrotational, flow governed by (i) Conservation of mass with q the velocity, (what goes in comes out) div q = 0, (ii) Irrotationality, curl q = 0. The pressure is given by Bernoulli's law, p = p(\q\). These equations are equivalent to the Cauchy-Riemann equations and so lots of problems can be solved. But there is an anomaly — there is no drag and for that matter often no lift i.e. no net force on the object which for our purposes and from here on is a cross section of a wing. By taking a nonsymmetric cross section that has a cusp at the end and requiring that the flow has a finite velocity we obtain a flow with lift but still no drag.
    [Show full text]
  • The Wind Tunnel That Busemann's 1935 Supersonic Swept Wing Theory (Ref* I.) A1 So Appl Ied to Subsonic Compressi Bi1 Ity Effects (Ref
    VORTEX LIFT RESEARCH: EARLY CQNTRIBUTTO~SAND SOME CURRENT CHALLENGES Edward C. Pol hamus NASA Langley Research Center Hampton, Vi i-gi nia SUMMARY This paper briefly reviews the trend towards slender-wing aircraft for supersonic cruise and the early chronology of research directed towards their vortex- 1 ift characteristics. An overview of the devel opment of vortex-1 ift theoretical methods is presented, and some current computational and experimental challenges related to the viscous flow aspects of this vortex flow are discussed. INTRODUCTION Beginning with the first successful control 1ed fl ights of powered aircraft, there has been a continuing quest for ever-increasing speed, with supersonic flight emerging as one of the early goal s. The advantage of jet propulsion was recognized early, and by the late 1930's jet engines were in operation in several countries. High-speed wing design lagged somewhat behind, but by the mid 1940's it was generally accepted that supersonic flight could best be accomplished by the now well-known highly swept wing, often referred to as a "slender" wing. It was a1 so found that these wings tended to exhibit a new type of flow in which a highly stable vortex was formed along the leading edge, producing large increases in lift referred to as vortex lift. As this vortex flow phenomenon became better understood, it was added to the designers' options and is the subject of this conference. The purpose of this overview paper is to briefly summarize the early chronology of the development of slender-wi ng aerodynamic techno1 ogy, with emphasis on vortex lift research at Langley, and to discuss some current computational and experimental challenges.
    [Show full text]
  • An Overset Field-Panel Method for Unsteady Transonic Aeroelasticity
    24TH INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES An Overset Field-Panel Method for Unsteady Transonic Aeroelasticity P.C. Chen§, X.W. Gao¥, and L. Tang‡ ZONA Technology*, Scottsdale, AZ, www.zonatech.com Abstract process because it is independent of the The overset field-panel method presented in this structural characteristics, therefore it needs to paper solves the integral equation of the time- be computed only once and can be repeatedly linearized transonic small disturbance equation by used in a structural design loop. an overset field-panel scheme for rapid transonic aeroelastic applications of complex configurations. However, it is generally believed that the A block-tridiagonal approximation technique is unsteady panel methods are not applicable in developed to greatly improve the computational the transonic region because of the lack of the efficiency to solve the large size volume-cell transonic shock effects. On the other hand, the influence coefficient matrix. Using the high-fidelity Computational Fluid Dynamic (CFD) computational Fluid Dynamics solution as the methodology provides accurate transonic steady background flow, the present method shows solutions by solving the Euler’s or Navier- that simple theories based on the small disturbance Stokes’ equations, but it does not generate the approach can yield accurate unsteady transonic AIC matrix and cannot be effectively used for flow predictions. The aerodynamic influence coefficient matrix generated by the present method routine aeroelastic applications nor for an can be repeatedly used in a structural design loop; extensive structural design/optimization. rendering the present method as an ideal tool for Therefore, there is a great demand from the multi-disciplinary optimization.
    [Show full text]
  • Transonic Aeroelasticity: Theoretical and Computational Challenges
    Transonic Aeroelasticity: Theoretical and Computational Challenges Oddvar O. Bendiksen Department of Mechanical and Aerospace Engineering University of California, Los Angeles, CA Aeroelasticity Workshop DCTA - Brazil July 1-2, 2010 Introduction • Despite theoretical and experimental research extending over more than 50 years, we still do not have a good understanding of transonic flutter • Transonic flutter prediction remains among the most challenging problems in aeroelasticity, both from a theoretical and a computational standpoint • Problem is also of considerable practical importance, because - Large transport aircraft cruise at transonic Mach numbers - Supersonic fighters must be capable of sustained operation near Mach 1, where the flutter margin often is at a minimum O. Bendiksen UCLA Transonic Flutter Nonlinear Characteristics • For wings operating inside the transonic region Mcrit <<M∞ 1, strong oscillating shocks appear on upper and/or lower wing surfaces during flutter • Transonic flutter with shocks is strongly nonlinear - Wing thickness and angle of attack affect the flutter boundary - Airfoil shape becomes of importance (supercritical vs. conventional) - A mysterious transonic dip appears in the flutter boundary - Nonlinear aeroelastic mode interactions may occur Flutter 3 Speed Linear Theory Index U -----------------F - 2 bωα µ Flutter Boundary 1Transonic Dip 0.70.8 0.9 1.0 Mach No. M O. Bendiksen UCLA Transonic Dip Effect of Thickness and Angle of Attack 300 250 200 150 2% 100 4% 50 6% 8% 0 0.7 0.8 0.9 1 1.1 1.2 Mach No. M Dynamic pressure at flutter vs. Mach number Effect of angle of attack on experimental flutter for a swept series of wings of different airfoil boundary and transonic dip of NLR 7301 2D thickness (Dogget, et al., NASA Langley) aeroelastic model tested at DLR (Schewe, et al.) O.
    [Show full text]
  • 7. Transonic Aerodynamics of Airfoils and Wings
    W.H. Mason 7. Transonic Aerodynamics of Airfoils and Wings 7.1 Introduction Transonic flow occurs when there is mixed sub- and supersonic local flow in the same flowfield (typically with freestream Mach numbers from M = 0.6 or 0.7 to 1.2). Usually the supersonic region of the flow is terminated by a shock wave, allowing the flow to slow down to subsonic speeds. This complicates both computations and wind tunnel testing. It also means that there is very little analytic theory available for guidance in designing for transonic flow conditions. Importantly, not only is the outer inviscid portion of the flow governed by nonlinear flow equations, but the nonlinear flow features typically require that viscous effects be included immediately in the flowfield analysis for accurate design and analysis work. Note also that hypersonic vehicles with bow shocks necessarily have a region of subsonic flow behind the shock, so there is an element of transonic flow on those vehicles too. In the days of propeller airplanes the transonic flow limitations on the propeller mostly kept airplanes from flying fast enough to encounter transonic flow over the rest of the airplane. Here the propeller was moving much faster than the airplane, and adverse transonic aerodynamic problems appeared on the prop first, limiting the speed and thus transonic flow problems over the rest of the aircraft. However, WWII fighters could reach transonic speeds in a dive, and major problems often arose. One notable example was the Lockheed P-38 Lightning. Transonic effects prevented the airplane from readily recovering from dives, and during one flight test, Lockheed test pilot Ralph Virden had a fatal accident.
    [Show full text]
  • SIMULATION of UNSTEADY ROTATIONAL FLOW OVER PROPFAN CONFIGURATION NASA GRANT No. NAG 3-730 FINAL REPORT for the Period JUNE 1986
    SIMULATION OF UNSTEADY ROTATIONAL FLOW OVER PROPFAN CONFIGURATION NASA GRANT No. NAG 3-730 FINAL REPORT for the period JUNE 1986 - NOVEMBER 30, 1990 submitted to NASA LEWIS RESEARCH CENTER CLEVELAND, OHIO Attn: Mr. G. L. Stefko Project Monitor Prepared by: Rakesh Srivastava Post Doctoral Fellow L. N. Sankar Associate Professor School of Aerospace Engineering Georgia Institute of Technology Atlanta, Georgia 30332 INTRODUCTION During the past decade, aircraft engine manufacturers and scientists at NASA have worked on extending the high propulsive efficiency of a classical propeller to higher cruise Mach numbers. The resulting configurations use highly swept twisted and very thin blades to delay the drag divergence Mach number. Unfortunately, these blades are also susceptible to aeroelastic instabilities. This was observed for some advanced propeller configurations in wind tunnel tests at NASA Lewis Research Center, where the blades fluttered at cruise speeds. To address this problem and to understand the flow phenomena and the solid fluid interaction involved, a research effort was initiated at Georgia Institute of Technology in 1986, under the support of the Structural Dynamics Branch of the NASA Lewis Research Center. The objectives of this study are: a) Development of solution procedures and computer codes capable of predicting the aeroelastic characteristics of modern single and counter-rotation propellers, b) Use of these solution procedures to understand physical phenomena such as stall flutter, transonic flutter and divergence Towards this goal a two dimensional compressible Navier-Stokes solver and a three dimensional compressible Euler solver have been developed and documented in open literature. The two dimensional unsteady, compressible Navier-Stokes solver developed at Georgia Institute of Technology has been used to study a two dimensional propfan like airfoil operating in high speed transonic flow regime.
    [Show full text]
  • ON the RANGE of APPLICABILITY of the TRANSONIC AREA RULE by John R. Spreiter Ames Aeronautical Laboratory Moffett Field, Calif
    -1 TECHNICAL NOTE 3673 L 1 ON THE RANGE OF APPLICABILITY OF THE TRANSONIC AREA RULE By John R. Spreiter Ames Aeronautical Laboratory Moffett Field, Calif. Washington May 1956 I I t --- . .. .. .... .J TECH LIBRARY KAFB.—,NM----- NATIONAL ADVISORY COMMITTEE FOR -OilAUTICS ~ III!IIMIIMI!MI! 011bb3B3 . TECHNICAL NOTE 3673 ON THE RANGE OF APPLICAKCKHY OF THE TRANSONIC AREA RULE= By John R. Spreiter suMMARY Some insight into the range of applicability of the transonic area rule has been gained by’comparison with the appropriate similarity rule of transonic flow theory and with available experimental data for a large family of rectangular wings having NACA 6W#K profiles. In spite of the small number of geometric variables available for such a family, the range is sufficient that cases both compatible and incompatible with the area rule are included. INTRODUCTION A great deal of effort is presently being expended in correlating the zero-lift drag rise of wing-body combinations on the basis of their streamwise distribution of cross-section area. This work is based on the discovery and generalization announced by Whitconb in reference 1 that “near the speed of sound, the zero-lift drag rise of thin low-aspect-ratio wing-body combinations is primarily dependent on the axial distribution of cross-sectional area normal to the air stream.” It is further conjec- tured in reference 1 that this concept, bOTm = the transo~c area rulej is valid for wings with moderate twist and camber. Since an accurate pre- diction of drag is of vital importance to the designer, and since the use of such a simple rule is appealing, it is a matter of great and immediate concern to investigate the applicability of the transonic area rule to the widest possible variety of shapes of aerodynamic interest.
    [Show full text]
  • Propfan Test Assessment Testbed Aircraft Stability and Controvperformance 1/9-Scale Wind Tunnel Tests
    NASA Contractor Report 782727 Propfan Test Assessment Testbed Aircraft Stability and ControVPerformance 1/9-Scale Wind Tunnel Tests Bo HeLittle, Jr., K. H. Tomlin, A. S. Aljabri, and C. A. Mason 2 Lockheed Aeronautical Systems Company Marietta, Georgia May 1988 Prepared for Lewis Research Center Under Contract NAS3-24339 National Aeronauttcs and Space Administration 821 21) FROPPAilf TEST ~~~~SS~~~~~W 8 8- 263 6 2ESTBED AIBCRA ABILITY BFJD ~~~~~O~/~~~~~R BNCE 1/9-SCALE WIND TU^^^^ TESTS Final. Re at (Lockheed ~~~~~~a~~ic~~Uilnclas Systerns CO,) 4952 FOREWORD These tests were performed in three separate NASA wind tunnels and required the support and cooperation of many NASA personnel. Appreciation is expressed to the management and personnel of the Langley 16-Ft Transonic Aerodynamics Wind Tunnel for their forbearance through eight long months, to the management and personnel of the Langley 4M x 7M Subsonic Wind Tunnel for their interest in and support of the program, and to the management and personnel of the Lewis 8-Ft x 6-Ft Supersonic Wind Tunnel for an expeditious conclusion. This work was performed under Contract NAS3-24339 from NASA-Lewis Research Center. This report is submitted to satisfy the requirements of DRD 220-04 of that contract. It is also identified as Lockheed Report No. LG88ER0056. PREGEDING PAGE BLANK NOT FILMED iii TABLE OF C0NTEN"S Sect ion -Title Page FOREWORD iii LIST OF FIGURES ix 1.0 SUMMARY 1 2.0 INTRODUCTION 3 3.0 TEST APPARATUS 5 3.1 Wind Tunnel Models 5 3.1.1 High-speed Tests 5 3.1.2 Low-Speed Tests 8 3.1.3
    [Show full text]
  • Section 7, Lecture 3: Effects of Wing Sweep
    Section 7, Lecture 3: Effects of Wing Sweep • All modern high-speed aircraft have swept wings: WHY? 1 MAE 5420 - Compressible Fluid Flow • Not in Anderson Supersonic Airfoils (revisited) • Normal Shock wave formed off the front of a blunt leading g=1.1 causes significant drag Detached shock waveg=1.3 Localized normal shock wave Credit: Selkirk College Professional Aviation Program 2 MAE 5420 - Compressible Fluid Flow Supersonic Airfoils (revisited, 2) • To eliminate this leading edge drag caused by detached bow wave Supersonic wings are typically quite sharp atg=1.1 the leading edge • Design feature allows oblique wave to attachg=1.3 to the leading edge eliminating the area of high pressure ahead of the wing. • Double wedge or “diamond” Airfoil section Credit: Selkirk College Professional Aviation Program 3 MAE 5420 - Compressible Fluid Flow Wing Design 101 • Subsonic Wing in Subsonic Flow • Subsonic Wing in Supersonic Flow • Supersonic Wing in Subsonic Flow A conundrum! • Supersonic Wing in Supersonic Flow • Wings that work well sub-sonically generally don’t work well supersonically, and vice-versa à Leading edge Wing-sweep can overcome problem with poor performance of sharp leading edge wing in subsonic flight. 4 MAE 5420 - Compressible Fluid Flow Wing Design 101 (2) • Compromise High-Sweep Delta design generates lift at low speeds • Highly-Swept Delta-Wing design … by increasing the angle-of-attack, works “pretty well” in both flow regimes but also has sufficient sweepback and slenderness to perform very Supersonic Subsonic efficiently at high speeds. • On a traditional aircraft wing a trailing vortex is formed only at the wing tips.
    [Show full text]